Unnamed Occurrence (ARDF - SR256; west shore of South Arm), Prince William Sound Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - SR256; west shore of South Arm)	- not defined -
Prince William Sound Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

This occurrence is not of economic significance, but it is a good example of structural control of ore deposits.
Location: The occurrence is located near tidewater on the west shore of South Arm of Bay of Isles. It is in the SE1/4 section 4, T. 3 N., R. 10 E., of the Seward Meridian. This is location 209 of Tysdal (1978 [MF-880-A]) and location S-70 of Jansons and others (1984). This location is accurate to within a quarter of a mile.
Geology: The occurrence consists of a thin chert lens a few feet long surrounded by graywacke (Kurtak and Jeske, 1986). Nelson and others (1985) mapped this area as Orca Group of early Teriary age. As much as 1 percent pyrite is concentrated at the chert and graywacke contact (Richter, 1965). Tysdal (1978 [MF-880-A]) indicated that chalcopyrite and pyrrhotite occurred in the shale (not graywacke) at its contact with the chert lens. A single sample from the mineralized graywacke contained 125 ppm copper and 481 ppm barium (Kurtak and Jeske, 1986).
Workings: A single sample from the mineralized graywacke contained 125 ppm copper and 481 ppm barium (Kurtak and Jeske, 1986). No workings or improvements are reported in the literature.
Age: Tertiary or younger; the occurrence is in rocks of the Orca Group of Tertiary age.

Commodities (Major) - Cu; (Minor) - Ba?
Development Status: None
Deposit Model: Besshi massive sulfide (Cox and Singer, 1986; model 24b)

Other Databases

Link to USGS - Alaska:	SR256

Other Regions, Features and Areas containing this locality

References